In many applications of a semiconductor chip accommodated in a package, e.g. in flip-chip applications, TSV applications (TSV=Through Silicon Via), WLB packages (WLB=Wafer Level Ball Grid Array) or in specific packages, such as e.g. eWLB packages (eWLB=embedded Wafer Level Ball Grid Array), it is often necessary to carry out a redistribution of the basic connection structure of the chip connection pins. This is generally carried out using a so-called “RDL layer” (RDL=Redistribution Layer). An RDL layer is applied by definition at the wafer level on the semiconductor substrate, i.e. on the BeOL stack (Backend-of-Line stack) of the processed semiconductor wafer.
A redistribution layer is thus a specific layer plane within a package that connects the I/O pads (input/output pads) of an integrated circuit to the bond pads of the package, i.e. the I/O pads of an integrated circuit are made available at other locations or positions, thereby simplifying chip-to-chip bonding.
Consequently, there is a need for a method for producing packaged MEMS assemblies comprising an RDL layer at the wafer level and a need for a corresponding packaged MEMS assembly.
In particular, there is a need for a production process which is relatively simple to implement and by means of which applying an RDL structure on a semiconductor wafer at which sensitive MEMS structures, such as e.g. membranes of a pressure sensor or of a capacitive sound transducer, are arranged can be realized.